The objectives of the Arizona SCOR are to determine the pathogeneses, natural histories, methods of early detection, and means of prevention and treatment of airways obstructive diseases (AOD). Fourteen closely related epidemiological, clinical, pathophysiological and experimental studies comprise a coordinated multidisciplinary program. An ongoing longitudinal study of greater 1650 Tucson households (greater 3800 persons) is continued to determine the natural history of AOD, to identify genetic and other risk factors as well as causative agents, and to evaluate methods for early detection. In this population, radiography will be evaluated as a tool for detection and categorization of AOD. In subpopulations, the SCOR will study: effects of environmental factors; relationships of atopy, asthma, and chronic AOD; and the utility of early detection and treatment of subclinical airways dysfunction. Pediatric lung function tests will be developed. Childhood airways diseases and their long-term consequences will be studied. Other studies will elucidate the development of anatomic changes and the nature and localization of the obstructive abnormality in AOD. Experimental studies relate structure to function (combining microfocal spot radiography with simultaneous physiologic and pathologic measurements), create animal models of AOD, and examine the alveolar macrophage response to irritants. A long-term study on the course and prognosis of clinical COPD will be continued. Studies of neural control of ventilation and of drug utilizaton in clinical AOD address neglected problems in the management of patients with advanced disease.